We propose to develop a biochip for parallel detection of thousands of microorganisms. It will serve as a genetic screen for the parallel detection, identification, and quantification of up to 10,000 unique microorganisms or gene targets and can be extended to include up to 30,000 targets in the near future. The need for such a comprehensive and broad-range screening tool has been recognized for years in many areas including diagnostics, air, water, food, animal, and plant safety, and bioprocess monitoring. However, its development was hampered by the ability to synthesize and test thousands of possible probes rapidly and economically. This problem is solved now because of the invention of a highly flexible and low-cost in-situ oligonucleotide biochip synthesis platform by the University of Michigan and Xeotron. It can produce biochips overnight without costing a fortune. It is highly flexible with respect to probe content which is software controlled. It uses traditional DNA synthesis chemistry modified to respond to light and thousands of microfluidic reactor array etched on silicon surface. [unreadable] [unreadable] This proposal combines the expertise in bioinformatics, phylogenetics, environmental engineering, and data interpretation for mixed microbial systems available at the Center for Microbial Ecology (CME) at Michigan State University (MSU) with the flexible biochip fabrication technology described above. Probes for the biochip will be designed and validated by researchers at CME, which is a world leader in developing new methodologies to track and identify microbes in complex microbial systems. Synthesis of the biochip will be carried out by UM and Xeotron. Xeotron currently has a $9M phase one venture capital and is fully geared to produce any chip developed on this platform. Ability to detect all microorganisms of interest in a given matrix together will significantly improve the management of health concerns related to microorganisms. [unreadable] [unreadable]